Not the OP but Gnome does not support variable refresh rate.

I haven’t looked at the link you sent but you should not have any issues as Linux is a kernel.

Take a look at Hyprland, they have an xdg-desktop-portal implementation that apparently works with that stuff. https://github.com/hyprwm/xdg-desktop-portal-hyprland https://www.hyprland.org/

Do you possibly have two monitors? If so, Wayland is better for multiple monitors and different refresh rates.